Re: [RFC PATCH 0/3] Avoid soft lockup message when KVM is stopped by host
On 08/03/2011 05:24 PM, Eric B Munson wrote: This set is just a rough first pass at avoiding soft lockup warnings when a host pauses the execution of a guest. A flag is set by the host in the shared page used for the pvclock when the host goes to stop the guest. When the guest resumes and detects a soft lockup, this flag is checked and cleared and the soft lockup message is skipped. While this will cover the case were the host stops a guest, there will be other plain cases where the host is just over committed and will cause a softlockup false positive on the guest. Softlockup should use stolen time that makes use of the guest running info would cover both cases This currently breaks the build for non-x86 architectures but part of what I am looking for here is how to go about adding the function stubs for everything else. Eric B Munson (3): Add flag to indicate that a vm was stopped by the host Add functions to check if the host has stopped the vm Add check for suspended vm in softlockup detector arch/x86/include/asm/pvclock-abi.h |1 + arch/x86/include/asm/pvclock.h |3 +++ arch/x86/kernel/kvmclock.c | 12 kernel/watchdog.c | 11 +++ 4 files changed, 27 insertions(+), 0 deletions(-) -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [RFC PATCH 0/3] Avoid soft lockup message when KVM is stopped by host
On Wed, Aug 03, 2011 at 10:24:58AM -0400, Eric B Munson wrote: This set is just a rough first pass at avoiding soft lockup warnings when a host pauses the execution of a guest. A flag is set by the host in the shared page used for the pvclock when the host goes to stop the guest. When the guest resumes and detects a soft lockup, this flag is checked and cleared and the soft lockup message is skipped. This currently breaks the build for non-x86 architectures but part of what I am looking for here is how to go about adding the function stubs for everything else. To fix this, you can save/restore the offset added to kvmclock on vmstop/vmstart. See hw/kvmclock.c in the qemu source tree. -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [RFC PATCH 0/3] Avoid soft lockup message when KVM is stopped by host
On 08/04/2011 03:37 AM, Dor Laor wrote: On 08/03/2011 05:24 PM, Eric B Munson wrote: This set is just a rough first pass at avoiding soft lockup warnings when a host pauses the execution of a guest. A flag is set by the host in the shared page used for the pvclock when the host goes to stop the guest. When the guest resumes and detects a soft lockup, this flag is checked and cleared and the soft lockup message is skipped. While this will cover the case were the host stops a guest, there will be other plain cases where the host is just over committed and will cause a softlockup false positive on the guest. Softlockup should use stolen time that makes use of the guest running info would cover both cases At least in the current steal time implementation, there are numerous cases where steal time is not accounted but you'd hit a soft lockup. Pausing an idle guest via (qemu) stop is an example. Likewise, a guest that is descheduled while idle but then not scheduled for prolonged periods of time would also not be accounted as steal time. Regards, Anthony Liguori -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
